Measure the battery box area in both length and width. The determine how long the cables are and if they are long enough to reach to the front of the battery box assuming that the replacement battery is going to be 9 inches high. This is important because you might find a battery that will fit in the battery box, but the terminals are at the front of the battery when they are in proper orientation to where your positive and negative posts are located. Once you have this information in hand, then go to the place that you are going to purchase the battery, with ruler in hand, measure the choices that you have. I have found that Walmart has a good selection of the now current size available batteries, and the cost is quite reasonable. If you purchase a 1 year warranty battery, expect it to last not much more than 3 years under normal conditions. If you purchase a 2 year warranty battery, it will last between 4 and 5 years usually. I never consider the 3 year warranty batteries because they are not worth the premium price that they cost. If you need a 6 volt battery, then your choices of purchase locations is limited to auto parts stores, or such locations as a Interstate battery dealer. I don't remember ever seeing a 6 volt battery in Walmart. Also expect to pay a lot more for the 6 volt battery, since the cost of manufacturing is greater and the demand is less. Dusty